Description of slstructsize

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slstructsize

PURPOSE

SLSTRUCTSIZE Compute the size of a struct

SYNOPSIS

function nbytes = slstructsize(S, fields, types)

DESCRIPTION

SLSTRUCTSIZE Compute the size of a struct

 $ Syntax $
   - nbytes = slstructsize(S)
   - nbytes = slstructsize(S, fields)
   - nbytes = slstructsize(S, fields, types)

 $ Arguments $
   - nbytes:            the number of bytes in the specified parts of the struct
   - fields:            the fields that are counted in the computation
   - types:             the types of the fields when output

 $ Description $

   - nbytes = slstructsize(S) computes the bytes of the struct occupied
     if S is a struct-array, then the resultant nbytes is sum of all sizes
     of struct entries.

   - nbytes = slstructsize(S, fields) only computes the specified fields.
     If some specified fields are not in S, an error will be raised.

   - nbytes = slstructsize(S, fields, types) the computation will
     use the types for computing the size instead of using original types.

 $ History $
   - Created by Dahua Lin on Dec 10th, 2005

CROSS-REFERENCE INFORMATION

This function calls:

• slstructsize SLSTRUCTSIZE Compute the size of a struct
• sltypesize SLTYPESIZE Gets the element size of a specified type

This function is called by:

• slstructsize SLSTRUCTSIZE Compute the size of a struct

SOURCE CODE

0001 function nbytes = slstructsize(S, fields, types)
0002 %SLSTRUCTSIZE Compute the size of a struct
0003 %
0004 % $ Syntax $
0005 %   - nbytes = slstructsize(S)
0006 %   - nbytes = slstructsize(S, fields)
0007 %   - nbytes = slstructsize(S, fields, types)
0008 %
0009 % $ Arguments $
0010 %   - nbytes:            the number of bytes in the specified parts of the struct
0011 %   - fields:            the fields that are counted in the computation
0012 %   - types:             the types of the fields when output
0013 %
0014 % $ Description $
0015 %
0016 %   - nbytes = slstructsize(S) computes the bytes of the struct occupied
0017 %     if S is a struct-array, then the resultant nbytes is sum of all sizes
0018 %     of struct entries.
0019 %
0020 %   - nbytes = slstructsize(S, fields) only computes the specified fields.
0021 %     If some specified fields are not in S, an error will be raised.
0022 %
0023 %   - nbytes = slstructsize(S, fields, types) the computation will
0024 %     use the types for computing the size instead of using original types.
0025 %
0026 % $ History $
0027 %   - Created by Dahua Lin on Dec 10th, 2005
0028 %
0029 
0030 %% parse and verify input arguments
0031 if ~isstruct(S)
0032     error('S is not a struct');
0033 end
0034 if nargin < 2 || isempty(fields)
0035     fields = fieldnames(S);
0036 end
0037 if nargin < 3 || isempty(types)
0038     use_origin_types = true;
0039 else
0040     use_origin_types = false;
0041 end
0042 
0043 %% compute
0044 n = numel(S);
0045 if n == 1
0046     
0047     nbytes = 0;
0048     nterms = length(fields);
0049     
0050     for t = 1 : nterms
0051         cur_term = S.(fields{t});
0052         if isempty(cur_term)
0053             continue;
0054         elseif isstruct(cur_term)
0055             cur_nbytes = slstructsize(cur_term);
0056         else
0057             if use_origin_types || isempty(types{t})
0058                 cur_elem_bytes = sltypesize(class(cur_term));
0059             else
0060                 cur_elem_bytes = sltypesize(types{t});
0061             end
0062             cur_nbytes = cur_elem_bytes * numel(cur_term);
0063         end
0064         
0065         nbytes = nbytes + cur_nbytes;
0066     end
0067     
0068 else
0069     
0070     nbytes = 0;
0071     for i = 1 : n
0072         if use_origin_types
0073             nbytes = nbytes + slstructsize(S(i), fields);
0074         else
0075             nbytes = nbytes + slstructsize(S(i), fields, types);
0076         end
0077     end
0078     
0079 end
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